1. Field of the Invention
The present invention relates to an improved sealing structure for a mixing valve of hot and cool water, and especially to a mixing valve, wherein the sealing structure between the fixing disk and the lower wall of the casing is improved.
2. Description of the Prior Art
The prior art faucet mixes and regulates hot and cool water through a mixing valve, as shown in FIG. 4. In the structure of the mixing valve, two overlapped ceramic disks 51 and 52 are installed within a casing 53. One of the disks is fixed and another disk is controlled by a lever to move on the fixing disk. The movable disk 51 is installed with a mixing chamber 511 of cool and hot water, which is selectably connected one or two openings of water inlet to water outlet. In general, the fixing disk 52 is installed on the lower wall 531 of the casing, and two openings of water inlet are installed on the disk 5 and are connected to the separated hot and cool water guide openings (not shown in FIG. 4). An extra opening 521 is further installed on the disk 52 for transferring water to pass through a water outlet 532 to the opening of the faucet. Moreover, a sealing ring 55 is installed between the periphery of each water inlet and the water outlet and the lower wall of the casing 53 for providing sealing function between the fixing disk and the lower wall of the casing and between the water through holes.
In general, the sealing ring 55 is installed and positioned in the trench 533 on the lower wall of the casing and is protruded from the trench so as to resist to the bottom surface of the fixing disk 52. By the disk to compress the sealing ring 55 so as to achieve a required sealing effect. The sealing effect completely depends on the compressing force of the disk to the sealing ring. However, in some practical application, water flowing through the water through hole has larger flow speed or pressure so that the sealing ring displaces. Probably, one part of the sealing ring moves out of the fixing position or the trench. This abnormal condition will cause the sealing ring to be clamped between the disks and the positioning trench and then is deformed or worn so as to loss the required sealing function. Furthermore, in this way that by disks to compress and regulate the sealing effect of the sealing ring, it is probably that the fixing disk 52 and the movable disk 51 are tightly compressed with one another and thus the valve is difficult to be operated.
In order to overcome the defect in the prior art sealing device, various designs are disclosed. For example, Taiwan Patent No. 84205827 xe2x80x9can improved sealing structure for a mixing valve of hot and cool waterxe2x80x9d. As shown in FIGS. 5 and 6, a concave portion 535 having a shape with respect to that of the sealing ring 55 is installed on the lower wall 531 of the casing so that the sealing ring is located in the concave portion 535 not to protrude out of the edge of the concave portion. Then, by a rib 526 protruded downwards from the bottom of the fixing disk 52 and having a shape with respect to that of the concave portion so that during assembling, the rib 525 is guided into the concave portion 535 to steadily press the sealing ring 55. Thereby, the deformation of sealing ring is avoided and the sealing effect of the components are prevented.
In general conditions, by the aforesaid structure, the deformation of sealing ring is prevented, and a preferred sealing effect is attained by a slightly pressing force. However, this structure change needs to change the space formation of the lower wall 531 on the casing of the mixing valve, and the formation of the fixing disk 52 is also necessary to be changed. However, it is appreciated that the mixing valve of cool and hot water are used widely and the specifications of the parts are defined. Thus, most of the components are used commonly so as to reduce product cost. However, the design of the aforesaid patent must change some components, thus the sizes and molds must be redesigned, thus the cost is increased.
Another, during assembling these components, the rib 524 on the fixing disk must be embedded into the concave portion 535 on the lower wall of the casing accurately so to be properly pressed on the sealing ring 55 to attain a required sealing effect. Thus, it is difficult to be assembled. Moreover, during assembling, if the rib can not be accurately positioned to the concave portion, then sealing function will be lost completely.
Furthermore, according to the design, wherein the sealing ring is disposed in the concave portion on the lower wall of the casing, and then is pressed by the rib on the bottom surface of the fixing disk, the substantially sealing function is only limited at the strips of the outer most strip of the sealing ring (which is defined by the outer wall of the concave portion on the lower wall of the casing). However, the no sealing effect is generated by the inner strips on the periphery of water through hole of the sealing ring. Since for these strips, as the prior art sealing strips, the function of sealing is fully determined by the applied pressure. Thus, the defect as in the prior art is also existed.
Accordingly, the object of the present invention is to provide an improved sealing structure for a mixing valve of hot and cool water, wherein the sealing ring may be tightly engaged with a slightly pressing force. Therefore, the defect in the prior art sealing structure is avoided.
Another object of the present invention is to provide an improved sealing structure for a mixing valve of hot and cool water, wherein the strips of sealing ring is firmly positioned and has an identical sealing effect.
Another object of the present invention is to provide an improved sealing structure for a mixing valve of hot and cool water, wherein the assembly of components and the sealing ring can be performed easily and rapidly. After being assembling, the sealing ring is accurately positioned and has a preferred sealing effect.
A further object of the present invention is to provide an improved sealing structure for a mixing valve of hot and cool water, wherein the sealing between a fixing disk and the bottom of the casing is improved so that the cost and time are saved.
According to the aforementioned object, the bottom surface of the fixing disk and the lower wall of the casing are installed with respective first and second trenches having shapes symmetric to the trench of the sealing ring. The first and second trenches have wider openings and have a V shape and an inverse V shape cross section, respectively. Therefore, as the structure is assembled, the lower half of the sealing ring under the horizontal surface is engaged to the trench of the lower wall of the casing, and the upper half of the sealing ring above the horizontal surface is engaged to the trench in the bottom surface of the fixing disk so that the strips of the sealing ring are tightly adhered to the wall on the two sides of the contact trench. Therefore, a doubled sealing effect is obtained by a slightly pressing force. During assembling the aforementioned sealing structure, by the trenches having wider opening, the sealing ring can be engaged to the trench with a deeper depth so to be positioned therein. The structure of the present invention can be assembled easily.
The present invention will be better understood and its numerous objects and advantages will become apparent to those skilled in the art by referencing to the following drawings. Those skilled in the art should understand that these description only serves to embody the present invention, but not to confine the present invention. The spirit and scope of the present invention is fully defined with the appended claims in which: